This application relates to a method for removing a sealing plug from a casing or a wellbore in oil and gas recovery operations.
After a well is put into production, a wellhead is usually placed over the well at the ground surface and a closure device, such as a sealing cap, or the like, is provided at the wellhead to prevent the flow of production fluid from the well during certain circumstances. Sometimes, under these conditions, the closure device must be removed for replacement, repair, etc., which creates a risk that some production fluid from the well may flow out from the upper end of the well.
To overcome this, a sealing plug, also referred to as a packer, bridge plug or barrier plug, is usually inserted in the well and activated to plug, or seal, the well and prevent any escape of the production fluid out the top of the well. However, when it is desired to recap the well, the plug must be removed. One common technique for removing the plug is to employ a rig that is used to drill-out the sealing plug, or pull the plug from the well. However, this technique requires sophisticated equipment, is labor intensive, and therefore is expensive.
Another technique to remove the plug from the well is to implant a timing device in the plug to actuate an explosive in the plug after a predetermined time. However, this type of technique has drawbacks since, after these types of plugs have been set in the well, the operator may want to extend the life of the plug from the predetermined time to a longer period of time or even an indeterminate time, and to do so would not be possible.
Therefore, what is needed is a sealing plug of the above type which can be placed in the well to seal off the flow of production fluid as discussed above and yet can be removed at an indeterminate time in a relatively simple and inexpensive manner.